The carbon counter

Our planet’s terrestrial ecosystems play a critical role in mitigating climate change by absorbing approximately 30% of the carbon dioxide (CO2) emitted by human activity. This process, known as “land sink,” removes CO2 from the atmosphere and helps regulate the planet’s temperature and overall climate. But just how large is Earth’s capacity to absorb CO2? As we currently lack the means to quantify it, we cannot predict future climate scenarios and develop effective mitigation strategies.

Dr. Yinon Bar-On, who will join Weizmann’s Department of Earth and Planetary Sciences in March 2025, is tackling this issue using a combination of remote sensing, field observations, and various computational tools and models. 

One of the main challenges in understanding the land sink is quantifying how much carbon is absorbed from the atmosphere into various land-based reservoirs, such as living biomass, detritus, soil, and sediments. As these carbon pools have different turnover rates and are sensitive to both environmental and human-caused changes, understanding the carbon distribution between them will help us constrain—and perhaps even predict—the future dynamics of the land sink.

During his postdoctoral fellowship at the California Institute of Technology, where he worked with Profs. Woody Fischer and Christian Frankenberg in the Division of Geological and Planetary Sciences, Dr. Bar-On developed computational models to track how different land pools absorb CO2. Using a combination of field measurements and remote sensing techniques (optical, microwave, radar, etc.), he found that the majority of the carbon captured by the land sink in recent decades is stored in non-living reservoirs—e.g., soil, landfill, harvested wood products (such as furniture), and inland waters/dams. Yet, many of these pools are often undervalued in current land sink models. 

Tracking soil with AI 

At the Weizmann Institute, Dr. Bar-On plans to study the interface between biological and Earth sciences to better constrain the different components involved in the land sink. For example, he plans to develop methods to quantify the supply and removal of carbon from a key non‑living carbon pool: soil. He aims to use novel data-theory combinations to predict global dynamics in soil organic carbon (SOC), which is a key element that determines soil quality, fertility, agricultural utility and more. By employing streamlined yet robust SOC models and AI machine learning methods, Dr. Bar-On seeks to more accurately track the dynamics and distribution of SOC across time and space, providing a clearer picture of its global impact. 

He also aims to quantify the spatiotemporal dynamics of non-living carbon pools, such as harvested wood products, peatlands, river dams, and floodplains, to align existing models with real-world data.

Land sink resilience

Finally, Dr. Bar-On is exploring the impact of vegetation and photosynthesis on land sink dynamics. He plans to use solar-induced fluorescence (SIF)—a novel and promising remote-sensing approach that allows scientists to observe photosynthesis from space directly. By repurposing existing satellites, Dr. Bar-On intends to construct a unified, long-term record of changes in plant productivity and SIF.  This effort will unlock the opportunity to quantify the effects of the environment (e.g., temperature or droughts) and human activities (e.g., deforestation) on plant mortality and the resilience of the land sink.

Dr. Bar-On is fascinated by complex systems, such as our planet’s ecosystems, and figuring out how they work. Having earned his PhD studying quantitative biology in Prof. Ron Milo’s lab in the Institute’s Department of Plant and Environmental Sciences, Dr. Bar-On feels like he’s coming home, having gained a broader perspective, expanded to include Earth science and chemistry.

“Most places have either a strong plant science department or a strong Earth science department, but not both. To find strength in both fields at once—that’s rare,” he says, “That is what you find at Weizmann.”

Dr. Bar-On is married with two children.

Education and select awards

• BSc, summa cum laude, Tel Aviv University (2014)
• MSc (2016) and PhD (2022), Weizmann Institute of Science
• Postdoctoral Fellow (2023-2024), California Institute of Technology 
• Azrieli Foundation PhD Fellowship (2018-2022); Daniel Brenner Memorial Prize from the Weizmann Institute (2022); Rothschild Fellowship for Postdoctoral Studies (2023); Schmidt Science Fellow (2023), awarded by Schmidt Futures.